xref: /sqlite-3.40.0/src/insert.c (revision 85c6892a)
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** This file contains C code routines that are called by the parser
13 ** to handle INSERT statements in SQLite.
14 */
15 #include "sqliteInt.h"
16 
17 /*
18 ** Generate code that will
19 **
20 **   (1) acquire a lock for table pTab then
21 **   (2) open pTab as cursor iCur.
22 **
23 ** If pTab is a WITHOUT ROWID table, then it is the PRIMARY KEY index
24 ** for that table that is actually opened.
25 */
26 void sqlite3OpenTable(
27   Parse *pParse,  /* Generate code into this VDBE */
28   int iCur,       /* The cursor number of the table */
29   int iDb,        /* The database index in sqlite3.aDb[] */
30   Table *pTab,    /* The table to be opened */
31   int opcode      /* OP_OpenRead or OP_OpenWrite */
32 ){
33   Vdbe *v;
34   assert( !IsVirtual(pTab) );
35   v = sqlite3GetVdbe(pParse);
36   assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
37   sqlite3TableLock(pParse, iDb, pTab->tnum,
38                    (opcode==OP_OpenWrite)?1:0, pTab->zName);
39   if( HasRowid(pTab) ){
40     sqlite3VdbeAddOp4Int(v, opcode, iCur, pTab->tnum, iDb, pTab->nCol);
41     VdbeComment((v, "%s", pTab->zName));
42   }else{
43     Index *pPk = sqlite3PrimaryKeyIndex(pTab);
44     assert( pPk!=0 );
45     assert( pPk->tnum==pTab->tnum );
46     sqlite3VdbeAddOp3(v, opcode, iCur, pPk->tnum, iDb);
47     sqlite3VdbeSetP4KeyInfo(pParse, pPk);
48     VdbeComment((v, "%s", pTab->zName));
49   }
50 }
51 
52 /*
53 ** Return a pointer to the column affinity string associated with index
54 ** pIdx. A column affinity string has one character for each column in
55 ** the table, according to the affinity of the column:
56 **
57 **  Character      Column affinity
58 **  ------------------------------
59 **  'A'            BLOB
60 **  'B'            TEXT
61 **  'C'            NUMERIC
62 **  'D'            INTEGER
63 **  'F'            REAL
64 **
65 ** An extra 'D' is appended to the end of the string to cover the
66 ** rowid that appears as the last column in every index.
67 **
68 ** Memory for the buffer containing the column index affinity string
69 ** is managed along with the rest of the Index structure. It will be
70 ** released when sqlite3DeleteIndex() is called.
71 */
72 const char *sqlite3IndexAffinityStr(sqlite3 *db, Index *pIdx){
73   if( !pIdx->zColAff ){
74     /* The first time a column affinity string for a particular index is
75     ** required, it is allocated and populated here. It is then stored as
76     ** a member of the Index structure for subsequent use.
77     **
78     ** The column affinity string will eventually be deleted by
79     ** sqliteDeleteIndex() when the Index structure itself is cleaned
80     ** up.
81     */
82     int n;
83     Table *pTab = pIdx->pTable;
84     pIdx->zColAff = (char *)sqlite3DbMallocRaw(0, pIdx->nColumn+1);
85     if( !pIdx->zColAff ){
86       sqlite3OomFault(db);
87       return 0;
88     }
89     for(n=0; n<pIdx->nColumn; n++){
90       i16 x = pIdx->aiColumn[n];
91       if( x>=0 ){
92         pIdx->zColAff[n] = pTab->aCol[x].affinity;
93       }else if( x==XN_ROWID ){
94         pIdx->zColAff[n] = SQLITE_AFF_INTEGER;
95       }else{
96         char aff;
97         assert( x==XN_EXPR );
98         assert( pIdx->aColExpr!=0 );
99         aff = sqlite3ExprAffinity(pIdx->aColExpr->a[n].pExpr);
100         if( aff==0 ) aff = SQLITE_AFF_BLOB;
101         pIdx->zColAff[n] = aff;
102       }
103     }
104     pIdx->zColAff[n] = 0;
105   }
106 
107   return pIdx->zColAff;
108 }
109 
110 /*
111 ** Compute the affinity string for table pTab, if it has not already been
112 ** computed.  As an optimization, omit trailing SQLITE_AFF_BLOB affinities.
113 **
114 ** If the affinity exists (if it is no entirely SQLITE_AFF_BLOB values) and
115 ** if iReg>0 then code an OP_Affinity opcode that will set the affinities
116 ** for register iReg and following.  Or if affinities exists and iReg==0,
117 ** then just set the P4 operand of the previous opcode (which should  be
118 ** an OP_MakeRecord) to the affinity string.
119 **
120 ** A column affinity string has one character per column:
121 **
122 **  Character      Column affinity
123 **  ------------------------------
124 **  'A'            BLOB
125 **  'B'            TEXT
126 **  'C'            NUMERIC
127 **  'D'            INTEGER
128 **  'E'            REAL
129 */
130 void sqlite3TableAffinity(Vdbe *v, Table *pTab, int iReg){
131   int i;
132   char *zColAff = pTab->zColAff;
133   if( zColAff==0 ){
134     sqlite3 *db = sqlite3VdbeDb(v);
135     zColAff = (char *)sqlite3DbMallocRaw(0, pTab->nCol+1);
136     if( !zColAff ){
137       sqlite3OomFault(db);
138       return;
139     }
140 
141     for(i=0; i<pTab->nCol; i++){
142       zColAff[i] = pTab->aCol[i].affinity;
143     }
144     do{
145       zColAff[i--] = 0;
146     }while( i>=0 && zColAff[i]==SQLITE_AFF_BLOB );
147     pTab->zColAff = zColAff;
148   }
149   i = sqlite3Strlen30(zColAff);
150   if( i ){
151     if( iReg ){
152       sqlite3VdbeAddOp4(v, OP_Affinity, iReg, i, 0, zColAff, i);
153     }else{
154       sqlite3VdbeChangeP4(v, -1, zColAff, i);
155     }
156   }
157 }
158 
159 /*
160 ** Return non-zero if the table pTab in database iDb or any of its indices
161 ** have been opened at any point in the VDBE program. This is used to see if
162 ** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can
163 ** run without using a temporary table for the results of the SELECT.
164 */
165 static int readsTable(Parse *p, int iDb, Table *pTab){
166   Vdbe *v = sqlite3GetVdbe(p);
167   int i;
168   int iEnd = sqlite3VdbeCurrentAddr(v);
169 #ifndef SQLITE_OMIT_VIRTUALTABLE
170   VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;
171 #endif
172 
173   for(i=1; i<iEnd; i++){
174     VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
175     assert( pOp!=0 );
176     if( pOp->opcode==OP_OpenRead && pOp->p3==iDb ){
177       Index *pIndex;
178       int tnum = pOp->p2;
179       if( tnum==pTab->tnum ){
180         return 1;
181       }
182       for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
183         if( tnum==pIndex->tnum ){
184           return 1;
185         }
186       }
187     }
188 #ifndef SQLITE_OMIT_VIRTUALTABLE
189     if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pVTab ){
190       assert( pOp->p4.pVtab!=0 );
191       assert( pOp->p4type==P4_VTAB );
192       return 1;
193     }
194 #endif
195   }
196   return 0;
197 }
198 
199 #ifndef SQLITE_OMIT_AUTOINCREMENT
200 /*
201 ** Locate or create an AutoincInfo structure associated with table pTab
202 ** which is in database iDb.  Return the register number for the register
203 ** that holds the maximum rowid.  Return zero if pTab is not an AUTOINCREMENT
204 ** table.  (Also return zero when doing a VACUUM since we do not want to
205 ** update the AUTOINCREMENT counters during a VACUUM.)
206 **
207 ** There is at most one AutoincInfo structure per table even if the
208 ** same table is autoincremented multiple times due to inserts within
209 ** triggers.  A new AutoincInfo structure is created if this is the
210 ** first use of table pTab.  On 2nd and subsequent uses, the original
211 ** AutoincInfo structure is used.
212 **
213 ** Four consecutive registers are allocated:
214 **
215 **   (1)  The name of the pTab table.
216 **   (2)  The maximum ROWID of pTab.
217 **   (3)  The rowid in sqlite_sequence of pTab
218 **   (4)  The original value of the max ROWID in pTab, or NULL if none
219 **
220 ** The 2nd register is the one that is returned.  That is all the
221 ** insert routine needs to know about.
222 */
223 static int autoIncBegin(
224   Parse *pParse,      /* Parsing context */
225   int iDb,            /* Index of the database holding pTab */
226   Table *pTab         /* The table we are writing to */
227 ){
228   int memId = 0;      /* Register holding maximum rowid */
229   assert( pParse->db->aDb[iDb].pSchema!=0 );
230   if( (pTab->tabFlags & TF_Autoincrement)!=0
231    && (pParse->db->mDbFlags & DBFLAG_Vacuum)==0
232   ){
233     Parse *pToplevel = sqlite3ParseToplevel(pParse);
234     AutoincInfo *pInfo;
235     Table *pSeqTab = pParse->db->aDb[iDb].pSchema->pSeqTab;
236 
237     /* Verify that the sqlite_sequence table exists and is an ordinary
238     ** rowid table with exactly two columns.
239     ** Ticket d8dc2b3a58cd5dc2918a1d4acb 2018-05-23 */
240     if( pSeqTab==0
241      || !HasRowid(pSeqTab)
242      || IsVirtual(pSeqTab)
243      || pSeqTab->nCol!=2
244     ){
245       pParse->nErr++;
246       pParse->rc = SQLITE_CORRUPT_SEQUENCE;
247       return 0;
248     }
249 
250     pInfo = pToplevel->pAinc;
251     while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
252     if( pInfo==0 ){
253       pInfo = sqlite3DbMallocRawNN(pParse->db, sizeof(*pInfo));
254       if( pInfo==0 ) return 0;
255       pInfo->pNext = pToplevel->pAinc;
256       pToplevel->pAinc = pInfo;
257       pInfo->pTab = pTab;
258       pInfo->iDb = iDb;
259       pToplevel->nMem++;                  /* Register to hold name of table */
260       pInfo->regCtr = ++pToplevel->nMem;  /* Max rowid register */
261       pToplevel->nMem +=2;       /* Rowid in sqlite_sequence + orig max val */
262     }
263     memId = pInfo->regCtr;
264   }
265   return memId;
266 }
267 
268 /*
269 ** This routine generates code that will initialize all of the
270 ** register used by the autoincrement tracker.
271 */
272 void sqlite3AutoincrementBegin(Parse *pParse){
273   AutoincInfo *p;            /* Information about an AUTOINCREMENT */
274   sqlite3 *db = pParse->db;  /* The database connection */
275   Db *pDb;                   /* Database only autoinc table */
276   int memId;                 /* Register holding max rowid */
277   Vdbe *v = pParse->pVdbe;   /* VDBE under construction */
278 
279   /* This routine is never called during trigger-generation.  It is
280   ** only called from the top-level */
281   assert( pParse->pTriggerTab==0 );
282   assert( sqlite3IsToplevel(pParse) );
283 
284   assert( v );   /* We failed long ago if this is not so */
285   for(p = pParse->pAinc; p; p = p->pNext){
286     static const int iLn = VDBE_OFFSET_LINENO(2);
287     static const VdbeOpList autoInc[] = {
288       /* 0  */ {OP_Null,    0,  0, 0},
289       /* 1  */ {OP_Rewind,  0, 10, 0},
290       /* 2  */ {OP_Column,  0,  0, 0},
291       /* 3  */ {OP_Ne,      0,  9, 0},
292       /* 4  */ {OP_Rowid,   0,  0, 0},
293       /* 5  */ {OP_Column,  0,  1, 0},
294       /* 6  */ {OP_AddImm,  0,  0, 0},
295       /* 7  */ {OP_Copy,    0,  0, 0},
296       /* 8  */ {OP_Goto,    0, 11, 0},
297       /* 9  */ {OP_Next,    0,  2, 0},
298       /* 10 */ {OP_Integer, 0,  0, 0},
299       /* 11 */ {OP_Close,   0,  0, 0}
300     };
301     VdbeOp *aOp;
302     pDb = &db->aDb[p->iDb];
303     memId = p->regCtr;
304     assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
305     sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
306     sqlite3VdbeLoadString(v, memId-1, p->pTab->zName);
307     aOp = sqlite3VdbeAddOpList(v, ArraySize(autoInc), autoInc, iLn);
308     if( aOp==0 ) break;
309     aOp[0].p2 = memId;
310     aOp[0].p3 = memId+2;
311     aOp[2].p3 = memId;
312     aOp[3].p1 = memId-1;
313     aOp[3].p3 = memId;
314     aOp[3].p5 = SQLITE_JUMPIFNULL;
315     aOp[4].p2 = memId+1;
316     aOp[5].p3 = memId;
317     aOp[6].p1 = memId;
318     aOp[7].p2 = memId+2;
319     aOp[7].p1 = memId;
320     aOp[10].p2 = memId;
321   }
322 }
323 
324 /*
325 ** Update the maximum rowid for an autoincrement calculation.
326 **
327 ** This routine should be called when the regRowid register holds a
328 ** new rowid that is about to be inserted.  If that new rowid is
329 ** larger than the maximum rowid in the memId memory cell, then the
330 ** memory cell is updated.
331 */
332 static void autoIncStep(Parse *pParse, int memId, int regRowid){
333   if( memId>0 ){
334     sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
335   }
336 }
337 
338 /*
339 ** This routine generates the code needed to write autoincrement
340 ** maximum rowid values back into the sqlite_sequence register.
341 ** Every statement that might do an INSERT into an autoincrement
342 ** table (either directly or through triggers) needs to call this
343 ** routine just before the "exit" code.
344 */
345 static SQLITE_NOINLINE void autoIncrementEnd(Parse *pParse){
346   AutoincInfo *p;
347   Vdbe *v = pParse->pVdbe;
348   sqlite3 *db = pParse->db;
349 
350   assert( v );
351   for(p = pParse->pAinc; p; p = p->pNext){
352     static const int iLn = VDBE_OFFSET_LINENO(2);
353     static const VdbeOpList autoIncEnd[] = {
354       /* 0 */ {OP_NotNull,     0, 2, 0},
355       /* 1 */ {OP_NewRowid,    0, 0, 0},
356       /* 2 */ {OP_MakeRecord,  0, 2, 0},
357       /* 3 */ {OP_Insert,      0, 0, 0},
358       /* 4 */ {OP_Close,       0, 0, 0}
359     };
360     VdbeOp *aOp;
361     Db *pDb = &db->aDb[p->iDb];
362     int iRec;
363     int memId = p->regCtr;
364 
365     iRec = sqlite3GetTempReg(pParse);
366     assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
367     sqlite3VdbeAddOp3(v, OP_Le, memId+2, sqlite3VdbeCurrentAddr(v)+7, memId);
368     VdbeCoverage(v);
369     sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
370     aOp = sqlite3VdbeAddOpList(v, ArraySize(autoIncEnd), autoIncEnd, iLn);
371     if( aOp==0 ) break;
372     aOp[0].p1 = memId+1;
373     aOp[1].p2 = memId+1;
374     aOp[2].p1 = memId-1;
375     aOp[2].p3 = iRec;
376     aOp[3].p2 = iRec;
377     aOp[3].p3 = memId+1;
378     aOp[3].p5 = OPFLAG_APPEND;
379     sqlite3ReleaseTempReg(pParse, iRec);
380   }
381 }
382 void sqlite3AutoincrementEnd(Parse *pParse){
383   if( pParse->pAinc ) autoIncrementEnd(pParse);
384 }
385 #else
386 /*
387 ** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
388 ** above are all no-ops
389 */
390 # define autoIncBegin(A,B,C) (0)
391 # define autoIncStep(A,B,C)
392 #endif /* SQLITE_OMIT_AUTOINCREMENT */
393 
394 
395 /* Forward declaration */
396 static int xferOptimization(
397   Parse *pParse,        /* Parser context */
398   Table *pDest,         /* The table we are inserting into */
399   Select *pSelect,      /* A SELECT statement to use as the data source */
400   int onError,          /* How to handle constraint errors */
401   int iDbDest           /* The database of pDest */
402 );
403 
404 /*
405 ** This routine is called to handle SQL of the following forms:
406 **
407 **    insert into TABLE (IDLIST) values(EXPRLIST),(EXPRLIST),...
408 **    insert into TABLE (IDLIST) select
409 **    insert into TABLE (IDLIST) default values
410 **
411 ** The IDLIST following the table name is always optional.  If omitted,
412 ** then a list of all (non-hidden) columns for the table is substituted.
413 ** The IDLIST appears in the pColumn parameter.  pColumn is NULL if IDLIST
414 ** is omitted.
415 **
416 ** For the pSelect parameter holds the values to be inserted for the
417 ** first two forms shown above.  A VALUES clause is really just short-hand
418 ** for a SELECT statement that omits the FROM clause and everything else
419 ** that follows.  If the pSelect parameter is NULL, that means that the
420 ** DEFAULT VALUES form of the INSERT statement is intended.
421 **
422 ** The code generated follows one of four templates.  For a simple
423 ** insert with data coming from a single-row VALUES clause, the code executes
424 ** once straight down through.  Pseudo-code follows (we call this
425 ** the "1st template"):
426 **
427 **         open write cursor to <table> and its indices
428 **         put VALUES clause expressions into registers
429 **         write the resulting record into <table>
430 **         cleanup
431 **
432 ** The three remaining templates assume the statement is of the form
433 **
434 **   INSERT INTO <table> SELECT ...
435 **
436 ** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
437 ** in other words if the SELECT pulls all columns from a single table
438 ** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
439 ** if <table2> and <table1> are distinct tables but have identical
440 ** schemas, including all the same indices, then a special optimization
441 ** is invoked that copies raw records from <table2> over to <table1>.
442 ** See the xferOptimization() function for the implementation of this
443 ** template.  This is the 2nd template.
444 **
445 **         open a write cursor to <table>
446 **         open read cursor on <table2>
447 **         transfer all records in <table2> over to <table>
448 **         close cursors
449 **         foreach index on <table>
450 **           open a write cursor on the <table> index
451 **           open a read cursor on the corresponding <table2> index
452 **           transfer all records from the read to the write cursors
453 **           close cursors
454 **         end foreach
455 **
456 ** The 3rd template is for when the second template does not apply
457 ** and the SELECT clause does not read from <table> at any time.
458 ** The generated code follows this template:
459 **
460 **         X <- A
461 **         goto B
462 **      A: setup for the SELECT
463 **         loop over the rows in the SELECT
464 **           load values into registers R..R+n
465 **           yield X
466 **         end loop
467 **         cleanup after the SELECT
468 **         end-coroutine X
469 **      B: open write cursor to <table> and its indices
470 **      C: yield X, at EOF goto D
471 **         insert the select result into <table> from R..R+n
472 **         goto C
473 **      D: cleanup
474 **
475 ** The 4th template is used if the insert statement takes its
476 ** values from a SELECT but the data is being inserted into a table
477 ** that is also read as part of the SELECT.  In the third form,
478 ** we have to use an intermediate table to store the results of
479 ** the select.  The template is like this:
480 **
481 **         X <- A
482 **         goto B
483 **      A: setup for the SELECT
484 **         loop over the tables in the SELECT
485 **           load value into register R..R+n
486 **           yield X
487 **         end loop
488 **         cleanup after the SELECT
489 **         end co-routine R
490 **      B: open temp table
491 **      L: yield X, at EOF goto M
492 **         insert row from R..R+n into temp table
493 **         goto L
494 **      M: open write cursor to <table> and its indices
495 **         rewind temp table
496 **      C: loop over rows of intermediate table
497 **           transfer values form intermediate table into <table>
498 **         end loop
499 **      D: cleanup
500 */
501 void sqlite3Insert(
502   Parse *pParse,        /* Parser context */
503   SrcList *pTabList,    /* Name of table into which we are inserting */
504   Select *pSelect,      /* A SELECT statement to use as the data source */
505   IdList *pColumn,      /* Column names corresponding to IDLIST. */
506   int onError,          /* How to handle constraint errors */
507   Upsert *pUpsert       /* ON CONFLICT clauses for upsert, or NULL */
508 ){
509   sqlite3 *db;          /* The main database structure */
510   Table *pTab;          /* The table to insert into.  aka TABLE */
511   int i, j;             /* Loop counters */
512   Vdbe *v;              /* Generate code into this virtual machine */
513   Index *pIdx;          /* For looping over indices of the table */
514   int nColumn;          /* Number of columns in the data */
515   int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
516   int iDataCur = 0;     /* VDBE cursor that is the main data repository */
517   int iIdxCur = 0;      /* First index cursor */
518   int ipkColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
519   int endOfLoop;        /* Label for the end of the insertion loop */
520   int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
521   int addrInsTop = 0;   /* Jump to label "D" */
522   int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
523   SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
524   int iDb;              /* Index of database holding TABLE */
525   u8 useTempTable = 0;  /* Store SELECT results in intermediate table */
526   u8 appendFlag = 0;    /* True if the insert is likely to be an append */
527   u8 withoutRowid;      /* 0 for normal table.  1 for WITHOUT ROWID table */
528   u8 bIdListInOrder;    /* True if IDLIST is in table order */
529   ExprList *pList = 0;  /* List of VALUES() to be inserted  */
530 
531   /* Register allocations */
532   int regFromSelect = 0;/* Base register for data coming from SELECT */
533   int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
534   int regRowCount = 0;  /* Memory cell used for the row counter */
535   int regIns;           /* Block of regs holding rowid+data being inserted */
536   int regRowid;         /* registers holding insert rowid */
537   int regData;          /* register holding first column to insert */
538   int *aRegIdx = 0;     /* One register allocated to each index */
539 
540 #ifndef SQLITE_OMIT_TRIGGER
541   int isView;                 /* True if attempting to insert into a view */
542   Trigger *pTrigger;          /* List of triggers on pTab, if required */
543   int tmask;                  /* Mask of trigger times */
544 #endif
545 
546   db = pParse->db;
547   if( pParse->nErr || db->mallocFailed ){
548     goto insert_cleanup;
549   }
550   dest.iSDParm = 0;  /* Suppress a harmless compiler warning */
551 
552   /* If the Select object is really just a simple VALUES() list with a
553   ** single row (the common case) then keep that one row of values
554   ** and discard the other (unused) parts of the pSelect object
555   */
556   if( pSelect && (pSelect->selFlags & SF_Values)!=0 && pSelect->pPrior==0 ){
557     pList = pSelect->pEList;
558     pSelect->pEList = 0;
559     sqlite3SelectDelete(db, pSelect);
560     pSelect = 0;
561   }
562 
563   /* Locate the table into which we will be inserting new information.
564   */
565   assert( pTabList->nSrc==1 );
566   pTab = sqlite3SrcListLookup(pParse, pTabList);
567   if( pTab==0 ){
568     goto insert_cleanup;
569   }
570   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
571   assert( iDb<db->nDb );
572   if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0,
573                        db->aDb[iDb].zDbSName) ){
574     goto insert_cleanup;
575   }
576   withoutRowid = !HasRowid(pTab);
577 
578   /* Figure out if we have any triggers and if the table being
579   ** inserted into is a view
580   */
581 #ifndef SQLITE_OMIT_TRIGGER
582   pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
583   isView = pTab->pSelect!=0;
584 #else
585 # define pTrigger 0
586 # define tmask 0
587 # define isView 0
588 #endif
589 #ifdef SQLITE_OMIT_VIEW
590 # undef isView
591 # define isView 0
592 #endif
593   assert( (pTrigger && tmask) || (pTrigger==0 && tmask==0) );
594 
595   /* If pTab is really a view, make sure it has been initialized.
596   ** ViewGetColumnNames() is a no-op if pTab is not a view.
597   */
598   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
599     goto insert_cleanup;
600   }
601 
602   /* Cannot insert into a read-only table.
603   */
604   if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
605     goto insert_cleanup;
606   }
607 
608   /* Allocate a VDBE
609   */
610   v = sqlite3GetVdbe(pParse);
611   if( v==0 ) goto insert_cleanup;
612   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
613   sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);
614 
615 #ifndef SQLITE_OMIT_XFER_OPT
616   /* If the statement is of the form
617   **
618   **       INSERT INTO <table1> SELECT * FROM <table2>;
619   **
620   ** Then special optimizations can be applied that make the transfer
621   ** very fast and which reduce fragmentation of indices.
622   **
623   ** This is the 2nd template.
624   */
625   if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
626     assert( !pTrigger );
627     assert( pList==0 );
628     goto insert_end;
629   }
630 #endif /* SQLITE_OMIT_XFER_OPT */
631 
632   /* If this is an AUTOINCREMENT table, look up the sequence number in the
633   ** sqlite_sequence table and store it in memory cell regAutoinc.
634   */
635   regAutoinc = autoIncBegin(pParse, iDb, pTab);
636 
637   /* Allocate registers for holding the rowid of the new row,
638   ** the content of the new row, and the assembled row record.
639   */
640   regRowid = regIns = pParse->nMem+1;
641   pParse->nMem += pTab->nCol + 1;
642   if( IsVirtual(pTab) ){
643     regRowid++;
644     pParse->nMem++;
645   }
646   regData = regRowid+1;
647 
648   /* If the INSERT statement included an IDLIST term, then make sure
649   ** all elements of the IDLIST really are columns of the table and
650   ** remember the column indices.
651   **
652   ** If the table has an INTEGER PRIMARY KEY column and that column
653   ** is named in the IDLIST, then record in the ipkColumn variable
654   ** the index into IDLIST of the primary key column.  ipkColumn is
655   ** the index of the primary key as it appears in IDLIST, not as
656   ** is appears in the original table.  (The index of the INTEGER
657   ** PRIMARY KEY in the original table is pTab->iPKey.)
658   */
659   bIdListInOrder = (pTab->tabFlags & TF_OOOHidden)==0;
660   if( pColumn ){
661     for(i=0; i<pColumn->nId; i++){
662       pColumn->a[i].idx = -1;
663     }
664     for(i=0; i<pColumn->nId; i++){
665       for(j=0; j<pTab->nCol; j++){
666         if( sqlite3StrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
667           pColumn->a[i].idx = j;
668           if( i!=j ) bIdListInOrder = 0;
669           if( j==pTab->iPKey ){
670             ipkColumn = i;  assert( !withoutRowid );
671           }
672           break;
673         }
674       }
675       if( j>=pTab->nCol ){
676         if( sqlite3IsRowid(pColumn->a[i].zName) && !withoutRowid ){
677           ipkColumn = i;
678           bIdListInOrder = 0;
679         }else{
680           sqlite3ErrorMsg(pParse, "table %S has no column named %s",
681               pTabList, 0, pColumn->a[i].zName);
682           pParse->checkSchema = 1;
683           goto insert_cleanup;
684         }
685       }
686     }
687   }
688 
689   /* Figure out how many columns of data are supplied.  If the data
690   ** is coming from a SELECT statement, then generate a co-routine that
691   ** produces a single row of the SELECT on each invocation.  The
692   ** co-routine is the common header to the 3rd and 4th templates.
693   */
694   if( pSelect ){
695     /* Data is coming from a SELECT or from a multi-row VALUES clause.
696     ** Generate a co-routine to run the SELECT. */
697     int regYield;       /* Register holding co-routine entry-point */
698     int addrTop;        /* Top of the co-routine */
699     int rc;             /* Result code */
700 
701     regYield = ++pParse->nMem;
702     addrTop = sqlite3VdbeCurrentAddr(v) + 1;
703     sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
704     sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
705     dest.iSdst = bIdListInOrder ? regData : 0;
706     dest.nSdst = pTab->nCol;
707     rc = sqlite3Select(pParse, pSelect, &dest);
708     regFromSelect = dest.iSdst;
709     if( rc || db->mallocFailed || pParse->nErr ) goto insert_cleanup;
710     sqlite3VdbeEndCoroutine(v, regYield);
711     sqlite3VdbeJumpHere(v, addrTop - 1);                       /* label B: */
712     assert( pSelect->pEList );
713     nColumn = pSelect->pEList->nExpr;
714 
715     /* Set useTempTable to TRUE if the result of the SELECT statement
716     ** should be written into a temporary table (template 4).  Set to
717     ** FALSE if each output row of the SELECT can be written directly into
718     ** the destination table (template 3).
719     **
720     ** A temp table must be used if the table being updated is also one
721     ** of the tables being read by the SELECT statement.  Also use a
722     ** temp table in the case of row triggers.
723     */
724     if( pTrigger || readsTable(pParse, iDb, pTab) ){
725       useTempTable = 1;
726     }
727 
728     if( useTempTable ){
729       /* Invoke the coroutine to extract information from the SELECT
730       ** and add it to a transient table srcTab.  The code generated
731       ** here is from the 4th template:
732       **
733       **      B: open temp table
734       **      L: yield X, goto M at EOF
735       **         insert row from R..R+n into temp table
736       **         goto L
737       **      M: ...
738       */
739       int regRec;          /* Register to hold packed record */
740       int regTempRowid;    /* Register to hold temp table ROWID */
741       int addrL;           /* Label "L" */
742 
743       srcTab = pParse->nTab++;
744       regRec = sqlite3GetTempReg(pParse);
745       regTempRowid = sqlite3GetTempReg(pParse);
746       sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
747       addrL = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm); VdbeCoverage(v);
748       sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
749       sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
750       sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
751       sqlite3VdbeGoto(v, addrL);
752       sqlite3VdbeJumpHere(v, addrL);
753       sqlite3ReleaseTempReg(pParse, regRec);
754       sqlite3ReleaseTempReg(pParse, regTempRowid);
755     }
756   }else{
757     /* This is the case if the data for the INSERT is coming from a
758     ** single-row VALUES clause
759     */
760     NameContext sNC;
761     memset(&sNC, 0, sizeof(sNC));
762     sNC.pParse = pParse;
763     srcTab = -1;
764     assert( useTempTable==0 );
765     if( pList ){
766       nColumn = pList->nExpr;
767       if( sqlite3ResolveExprListNames(&sNC, pList) ){
768         goto insert_cleanup;
769       }
770     }else{
771       nColumn = 0;
772     }
773   }
774 
775   /* If there is no IDLIST term but the table has an integer primary
776   ** key, the set the ipkColumn variable to the integer primary key
777   ** column index in the original table definition.
778   */
779   if( pColumn==0 && nColumn>0 ){
780     ipkColumn = pTab->iPKey;
781   }
782 
783   /* Make sure the number of columns in the source data matches the number
784   ** of columns to be inserted into the table.
785   */
786   for(i=0; i<pTab->nCol; i++){
787     nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
788   }
789   if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
790     sqlite3ErrorMsg(pParse,
791        "table %S has %d columns but %d values were supplied",
792        pTabList, 0, pTab->nCol-nHidden, nColumn);
793     goto insert_cleanup;
794   }
795   if( pColumn!=0 && nColumn!=pColumn->nId ){
796     sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
797     goto insert_cleanup;
798   }
799 
800   /* Initialize the count of rows to be inserted
801   */
802   if( (db->flags & SQLITE_CountRows)!=0
803    && !pParse->nested
804    && !pParse->pTriggerTab
805   ){
806     regRowCount = ++pParse->nMem;
807     sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
808   }
809 
810   /* If this is not a view, open the table and and all indices */
811   if( !isView ){
812     int nIdx;
813     nIdx = sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, -1, 0,
814                                       &iDataCur, &iIdxCur);
815     aRegIdx = sqlite3DbMallocRawNN(db, sizeof(int)*(nIdx+1));
816     if( aRegIdx==0 ){
817       goto insert_cleanup;
818     }
819     for(i=0, pIdx=pTab->pIndex; i<nIdx; pIdx=pIdx->pNext, i++){
820       assert( pIdx );
821       aRegIdx[i] = ++pParse->nMem;
822       pParse->nMem += pIdx->nColumn;
823     }
824   }
825 #ifndef SQLITE_OMIT_UPSERT
826   if( pUpsert ){
827     pTabList->a[0].iCursor = iDataCur;
828     pUpsert->pUpsertSrc = pTabList;
829     pUpsert->regData = regData;
830     pUpsert->iDataCur = iDataCur;
831     pUpsert->iIdxCur = iIdxCur;
832     if( pUpsert->pUpsertTarget ){
833       sqlite3UpsertAnalyzeTarget(pParse, pTabList, pUpsert);
834     }
835   }
836 #endif
837 
838 
839   /* This is the top of the main insertion loop */
840   if( useTempTable ){
841     /* This block codes the top of loop only.  The complete loop is the
842     ** following pseudocode (template 4):
843     **
844     **         rewind temp table, if empty goto D
845     **      C: loop over rows of intermediate table
846     **           transfer values form intermediate table into <table>
847     **         end loop
848     **      D: ...
849     */
850     addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab); VdbeCoverage(v);
851     addrCont = sqlite3VdbeCurrentAddr(v);
852   }else if( pSelect ){
853     /* This block codes the top of loop only.  The complete loop is the
854     ** following pseudocode (template 3):
855     **
856     **      C: yield X, at EOF goto D
857     **         insert the select result into <table> from R..R+n
858     **         goto C
859     **      D: ...
860     */
861     addrInsTop = addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
862     VdbeCoverage(v);
863   }
864 
865   /* Run the BEFORE and INSTEAD OF triggers, if there are any
866   */
867   endOfLoop = sqlite3VdbeMakeLabel(v);
868   if( tmask & TRIGGER_BEFORE ){
869     int regCols = sqlite3GetTempRange(pParse, pTab->nCol+1);
870 
871     /* build the NEW.* reference row.  Note that if there is an INTEGER
872     ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
873     ** translated into a unique ID for the row.  But on a BEFORE trigger,
874     ** we do not know what the unique ID will be (because the insert has
875     ** not happened yet) so we substitute a rowid of -1
876     */
877     if( ipkColumn<0 ){
878       sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
879     }else{
880       int addr1;
881       assert( !withoutRowid );
882       if( useTempTable ){
883         sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regCols);
884       }else{
885         assert( pSelect==0 );  /* Otherwise useTempTable is true */
886         sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regCols);
887       }
888       addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regCols); VdbeCoverage(v);
889       sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
890       sqlite3VdbeJumpHere(v, addr1);
891       sqlite3VdbeAddOp1(v, OP_MustBeInt, regCols); VdbeCoverage(v);
892     }
893 
894     /* Cannot have triggers on a virtual table. If it were possible,
895     ** this block would have to account for hidden column.
896     */
897     assert( !IsVirtual(pTab) );
898 
899     /* Create the new column data
900     */
901     for(i=j=0; i<pTab->nCol; i++){
902       if( pColumn ){
903         for(j=0; j<pColumn->nId; j++){
904           if( pColumn->a[j].idx==i ) break;
905         }
906       }
907       if( (!useTempTable && !pList) || (pColumn && j>=pColumn->nId)
908             || (pColumn==0 && IsOrdinaryHiddenColumn(&pTab->aCol[i])) ){
909         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regCols+i+1);
910       }else if( useTempTable ){
911         sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i+1);
912       }else{
913         assert( pSelect==0 ); /* Otherwise useTempTable is true */
914         sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i+1);
915       }
916       if( pColumn==0 && !IsOrdinaryHiddenColumn(&pTab->aCol[i]) ) j++;
917     }
918 
919     /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
920     ** do not attempt any conversions before assembling the record.
921     ** If this is a real table, attempt conversions as required by the
922     ** table column affinities.
923     */
924     if( !isView ){
925       sqlite3TableAffinity(v, pTab, regCols+1);
926     }
927 
928     /* Fire BEFORE or INSTEAD OF triggers */
929     sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE,
930         pTab, regCols-pTab->nCol-1, onError, endOfLoop);
931 
932     sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol+1);
933   }
934 
935   /* Compute the content of the next row to insert into a range of
936   ** registers beginning at regIns.
937   */
938   if( !isView ){
939     if( IsVirtual(pTab) ){
940       /* The row that the VUpdate opcode will delete: none */
941       sqlite3VdbeAddOp2(v, OP_Null, 0, regIns);
942     }
943     if( ipkColumn>=0 ){
944       if( useTempTable ){
945         sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regRowid);
946       }else if( pSelect ){
947         sqlite3VdbeAddOp2(v, OP_Copy, regFromSelect+ipkColumn, regRowid);
948       }else{
949         VdbeOp *pOp;
950         sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regRowid);
951         pOp = sqlite3VdbeGetOp(v, -1);
952         assert( pOp!=0 );
953         if( pOp->opcode==OP_Null && !IsVirtual(pTab) ){
954           appendFlag = 1;
955           pOp->opcode = OP_NewRowid;
956           pOp->p1 = iDataCur;
957           pOp->p2 = regRowid;
958           pOp->p3 = regAutoinc;
959         }
960       }
961       /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
962       ** to generate a unique primary key value.
963       */
964       if( !appendFlag ){
965         int addr1;
966         if( !IsVirtual(pTab) ){
967           addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid); VdbeCoverage(v);
968           sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
969           sqlite3VdbeJumpHere(v, addr1);
970         }else{
971           addr1 = sqlite3VdbeCurrentAddr(v);
972           sqlite3VdbeAddOp2(v, OP_IsNull, regRowid, addr1+2); VdbeCoverage(v);
973         }
974         sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid); VdbeCoverage(v);
975       }
976     }else if( IsVirtual(pTab) || withoutRowid ){
977       sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
978     }else{
979       sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
980       appendFlag = 1;
981     }
982     autoIncStep(pParse, regAutoinc, regRowid);
983 
984     /* Compute data for all columns of the new entry, beginning
985     ** with the first column.
986     */
987     nHidden = 0;
988     for(i=0; i<pTab->nCol; i++){
989       int iRegStore = regRowid+1+i;
990       if( i==pTab->iPKey ){
991         /* The value of the INTEGER PRIMARY KEY column is always a NULL.
992         ** Whenever this column is read, the rowid will be substituted
993         ** in its place.  Hence, fill this column with a NULL to avoid
994         ** taking up data space with information that will never be used.
995         ** As there may be shallow copies of this value, make it a soft-NULL */
996         sqlite3VdbeAddOp1(v, OP_SoftNull, iRegStore);
997         continue;
998       }
999       if( pColumn==0 ){
1000         if( IsHiddenColumn(&pTab->aCol[i]) ){
1001           j = -1;
1002           nHidden++;
1003         }else{
1004           j = i - nHidden;
1005         }
1006       }else{
1007         for(j=0; j<pColumn->nId; j++){
1008           if( pColumn->a[j].idx==i ) break;
1009         }
1010       }
1011       if( j<0 || nColumn==0 || (pColumn && j>=pColumn->nId) ){
1012         sqlite3ExprCodeFactorable(pParse, pTab->aCol[i].pDflt, iRegStore);
1013       }else if( useTempTable ){
1014         sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, iRegStore);
1015       }else if( pSelect ){
1016         if( regFromSelect!=regData ){
1017           sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+j, iRegStore);
1018         }
1019       }else{
1020         sqlite3ExprCode(pParse, pList->a[j].pExpr, iRegStore);
1021       }
1022     }
1023 
1024     /* Generate code to check constraints and generate index keys and
1025     ** do the insertion.
1026     */
1027 #ifndef SQLITE_OMIT_VIRTUALTABLE
1028     if( IsVirtual(pTab) ){
1029       const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
1030       sqlite3VtabMakeWritable(pParse, pTab);
1031       sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
1032       sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
1033       sqlite3MayAbort(pParse);
1034     }else
1035 #endif
1036     {
1037       int isReplace;    /* Set to true if constraints may cause a replace */
1038       int bUseSeek;     /* True to use OPFLAG_SEEKRESULT */
1039       sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
1040           regIns, 0, ipkColumn>=0, onError, endOfLoop, &isReplace, 0, pUpsert
1041       );
1042       sqlite3FkCheck(pParse, pTab, 0, regIns, 0, 0);
1043 
1044       /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
1045       ** constraints or (b) there are no triggers and this table is not a
1046       ** parent table in a foreign key constraint. It is safe to set the
1047       ** flag in the second case as if any REPLACE constraint is hit, an
1048       ** OP_Delete or OP_IdxDelete instruction will be executed on each
1049       ** cursor that is disturbed. And these instructions both clear the
1050       ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
1051       ** functionality.  */
1052       bUseSeek = (isReplace==0 || (pTrigger==0 &&
1053           ((db->flags & SQLITE_ForeignKeys)==0 || sqlite3FkReferences(pTab)==0)
1054       ));
1055       sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
1056           regIns, aRegIdx, 0, appendFlag, bUseSeek
1057       );
1058     }
1059   }
1060 
1061   /* Update the count of rows that are inserted
1062   */
1063   if( regRowCount ){
1064     sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
1065   }
1066 
1067   if( pTrigger ){
1068     /* Code AFTER triggers */
1069     sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER,
1070         pTab, regData-2-pTab->nCol, onError, endOfLoop);
1071   }
1072 
1073   /* The bottom of the main insertion loop, if the data source
1074   ** is a SELECT statement.
1075   */
1076   sqlite3VdbeResolveLabel(v, endOfLoop);
1077   if( useTempTable ){
1078     sqlite3VdbeAddOp2(v, OP_Next, srcTab, addrCont); VdbeCoverage(v);
1079     sqlite3VdbeJumpHere(v, addrInsTop);
1080     sqlite3VdbeAddOp1(v, OP_Close, srcTab);
1081   }else if( pSelect ){
1082     sqlite3VdbeGoto(v, addrCont);
1083     sqlite3VdbeJumpHere(v, addrInsTop);
1084   }
1085 
1086 insert_end:
1087   /* Update the sqlite_sequence table by storing the content of the
1088   ** maximum rowid counter values recorded while inserting into
1089   ** autoincrement tables.
1090   */
1091   if( pParse->nested==0 && pParse->pTriggerTab==0 ){
1092     sqlite3AutoincrementEnd(pParse);
1093   }
1094 
1095   /*
1096   ** Return the number of rows inserted. If this routine is
1097   ** generating code because of a call to sqlite3NestedParse(), do not
1098   ** invoke the callback function.
1099   */
1100   if( regRowCount ){
1101     sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
1102     sqlite3VdbeSetNumCols(v, 1);
1103     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", SQLITE_STATIC);
1104   }
1105 
1106 insert_cleanup:
1107   sqlite3SrcListDelete(db, pTabList);
1108   sqlite3ExprListDelete(db, pList);
1109   sqlite3UpsertDelete(db, pUpsert);
1110   sqlite3SelectDelete(db, pSelect);
1111   sqlite3IdListDelete(db, pColumn);
1112   sqlite3DbFree(db, aRegIdx);
1113 }
1114 
1115 /* Make sure "isView" and other macros defined above are undefined. Otherwise
1116 ** they may interfere with compilation of other functions in this file
1117 ** (or in another file, if this file becomes part of the amalgamation).  */
1118 #ifdef isView
1119  #undef isView
1120 #endif
1121 #ifdef pTrigger
1122  #undef pTrigger
1123 #endif
1124 #ifdef tmask
1125  #undef tmask
1126 #endif
1127 
1128 /*
1129 ** Meanings of bits in of pWalker->eCode for
1130 ** sqlite3ExprReferencesUpdatedColumn()
1131 */
1132 #define CKCNSTRNT_COLUMN   0x01    /* CHECK constraint uses a changing column */
1133 #define CKCNSTRNT_ROWID    0x02    /* CHECK constraint references the ROWID */
1134 
1135 /* This is the Walker callback from sqlite3ExprReferencesUpdatedColumn().
1136 *  Set bit 0x01 of pWalker->eCode if pWalker->eCode to 0 and if this
1137 ** expression node references any of the
1138 ** columns that are being modifed by an UPDATE statement.
1139 */
1140 static int checkConstraintExprNode(Walker *pWalker, Expr *pExpr){
1141   if( pExpr->op==TK_COLUMN ){
1142     assert( pExpr->iColumn>=0 || pExpr->iColumn==-1 );
1143     if( pExpr->iColumn>=0 ){
1144       if( pWalker->u.aiCol[pExpr->iColumn]>=0 ){
1145         pWalker->eCode |= CKCNSTRNT_COLUMN;
1146       }
1147     }else{
1148       pWalker->eCode |= CKCNSTRNT_ROWID;
1149     }
1150   }
1151   return WRC_Continue;
1152 }
1153 
1154 /*
1155 ** pExpr is a CHECK constraint on a row that is being UPDATE-ed.  The
1156 ** only columns that are modified by the UPDATE are those for which
1157 ** aiChng[i]>=0, and also the ROWID is modified if chngRowid is true.
1158 **
1159 ** Return true if CHECK constraint pExpr uses any of the
1160 ** changing columns (or the rowid if it is changing).  In other words,
1161 ** return true if this CHECK constraint must be validated for
1162 ** the new row in the UPDATE statement.
1163 **
1164 ** 2018-09-15: pExpr might also be an expression for an index-on-expressions.
1165 ** The operation of this routine is the same - return true if an only if
1166 ** the expression uses one or more of columns identified by the second and
1167 ** third arguments.
1168 */
1169 int sqlite3ExprReferencesUpdatedColumn(
1170   Expr *pExpr,    /* The expression to be checked */
1171   int *aiChng,    /* aiChng[x]>=0 if column x changed by the UPDATE */
1172   int chngRowid   /* True if UPDATE changes the rowid */
1173 ){
1174   Walker w;
1175   memset(&w, 0, sizeof(w));
1176   w.eCode = 0;
1177   w.xExprCallback = checkConstraintExprNode;
1178   w.u.aiCol = aiChng;
1179   sqlite3WalkExpr(&w, pExpr);
1180   if( !chngRowid ){
1181     testcase( (w.eCode & CKCNSTRNT_ROWID)!=0 );
1182     w.eCode &= ~CKCNSTRNT_ROWID;
1183   }
1184   testcase( w.eCode==0 );
1185   testcase( w.eCode==CKCNSTRNT_COLUMN );
1186   testcase( w.eCode==CKCNSTRNT_ROWID );
1187   testcase( w.eCode==(CKCNSTRNT_ROWID|CKCNSTRNT_COLUMN) );
1188   return w.eCode!=0;
1189 }
1190 
1191 /*
1192 ** Generate code to do constraint checks prior to an INSERT or an UPDATE
1193 ** on table pTab.
1194 **
1195 ** The regNewData parameter is the first register in a range that contains
1196 ** the data to be inserted or the data after the update.  There will be
1197 ** pTab->nCol+1 registers in this range.  The first register (the one
1198 ** that regNewData points to) will contain the new rowid, or NULL in the
1199 ** case of a WITHOUT ROWID table.  The second register in the range will
1200 ** contain the content of the first table column.  The third register will
1201 ** contain the content of the second table column.  And so forth.
1202 **
1203 ** The regOldData parameter is similar to regNewData except that it contains
1204 ** the data prior to an UPDATE rather than afterwards.  regOldData is zero
1205 ** for an INSERT.  This routine can distinguish between UPDATE and INSERT by
1206 ** checking regOldData for zero.
1207 **
1208 ** For an UPDATE, the pkChng boolean is true if the true primary key (the
1209 ** rowid for a normal table or the PRIMARY KEY for a WITHOUT ROWID table)
1210 ** might be modified by the UPDATE.  If pkChng is false, then the key of
1211 ** the iDataCur content table is guaranteed to be unchanged by the UPDATE.
1212 **
1213 ** For an INSERT, the pkChng boolean indicates whether or not the rowid
1214 ** was explicitly specified as part of the INSERT statement.  If pkChng
1215 ** is zero, it means that the either rowid is computed automatically or
1216 ** that the table is a WITHOUT ROWID table and has no rowid.  On an INSERT,
1217 ** pkChng will only be true if the INSERT statement provides an integer
1218 ** value for either the rowid column or its INTEGER PRIMARY KEY alias.
1219 **
1220 ** The code generated by this routine will store new index entries into
1221 ** registers identified by aRegIdx[].  No index entry is created for
1222 ** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
1223 ** the same as the order of indices on the linked list of indices
1224 ** at pTab->pIndex.
1225 **
1226 ** The caller must have already opened writeable cursors on the main
1227 ** table and all applicable indices (that is to say, all indices for which
1228 ** aRegIdx[] is not zero).  iDataCur is the cursor for the main table when
1229 ** inserting or updating a rowid table, or the cursor for the PRIMARY KEY
1230 ** index when operating on a WITHOUT ROWID table.  iIdxCur is the cursor
1231 ** for the first index in the pTab->pIndex list.  Cursors for other indices
1232 ** are at iIdxCur+N for the N-th element of the pTab->pIndex list.
1233 **
1234 ** This routine also generates code to check constraints.  NOT NULL,
1235 ** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
1236 ** then the appropriate action is performed.  There are five possible
1237 ** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
1238 **
1239 **  Constraint type  Action       What Happens
1240 **  ---------------  ----------   ----------------------------------------
1241 **  any              ROLLBACK     The current transaction is rolled back and
1242 **                                sqlite3_step() returns immediately with a
1243 **                                return code of SQLITE_CONSTRAINT.
1244 **
1245 **  any              ABORT        Back out changes from the current command
1246 **                                only (do not do a complete rollback) then
1247 **                                cause sqlite3_step() to return immediately
1248 **                                with SQLITE_CONSTRAINT.
1249 **
1250 **  any              FAIL         Sqlite3_step() returns immediately with a
1251 **                                return code of SQLITE_CONSTRAINT.  The
1252 **                                transaction is not rolled back and any
1253 **                                changes to prior rows are retained.
1254 **
1255 **  any              IGNORE       The attempt in insert or update the current
1256 **                                row is skipped, without throwing an error.
1257 **                                Processing continues with the next row.
1258 **                                (There is an immediate jump to ignoreDest.)
1259 **
1260 **  NOT NULL         REPLACE      The NULL value is replace by the default
1261 **                                value for that column.  If the default value
1262 **                                is NULL, the action is the same as ABORT.
1263 **
1264 **  UNIQUE           REPLACE      The other row that conflicts with the row
1265 **                                being inserted is removed.
1266 **
1267 **  CHECK            REPLACE      Illegal.  The results in an exception.
1268 **
1269 ** Which action to take is determined by the overrideError parameter.
1270 ** Or if overrideError==OE_Default, then the pParse->onError parameter
1271 ** is used.  Or if pParse->onError==OE_Default then the onError value
1272 ** for the constraint is used.
1273 */
1274 void sqlite3GenerateConstraintChecks(
1275   Parse *pParse,       /* The parser context */
1276   Table *pTab,         /* The table being inserted or updated */
1277   int *aRegIdx,        /* Use register aRegIdx[i] for index i.  0 for unused */
1278   int iDataCur,        /* Canonical data cursor (main table or PK index) */
1279   int iIdxCur,         /* First index cursor */
1280   int regNewData,      /* First register in a range holding values to insert */
1281   int regOldData,      /* Previous content.  0 for INSERTs */
1282   u8 pkChng,           /* Non-zero if the rowid or PRIMARY KEY changed */
1283   u8 overrideError,    /* Override onError to this if not OE_Default */
1284   int ignoreDest,      /* Jump to this label on an OE_Ignore resolution */
1285   int *pbMayReplace,   /* OUT: Set to true if constraint may cause a replace */
1286   int *aiChng,         /* column i is unchanged if aiChng[i]<0 */
1287   Upsert *pUpsert      /* ON CONFLICT clauses, if any.  NULL otherwise */
1288 ){
1289   Vdbe *v;             /* VDBE under constrution */
1290   Index *pIdx;         /* Pointer to one of the indices */
1291   Index *pPk = 0;      /* The PRIMARY KEY index */
1292   sqlite3 *db;         /* Database connection */
1293   int i;               /* loop counter */
1294   int ix;              /* Index loop counter */
1295   int nCol;            /* Number of columns */
1296   int onError;         /* Conflict resolution strategy */
1297   int addr1;           /* Address of jump instruction */
1298   int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
1299   int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
1300   Index *pUpIdx = 0;   /* Index to which to apply the upsert */
1301   u8 isUpdate;         /* True if this is an UPDATE operation */
1302   u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
1303   int upsertBypass = 0;  /* Address of Goto to bypass upsert subroutine */
1304   int upsertJump = 0;    /* Address of Goto that jumps into upsert subroutine */
1305   int ipkTop = 0;        /* Top of the IPK uniqueness check */
1306   int ipkBottom = 0;     /* OP_Goto at the end of the IPK uniqueness check */
1307 
1308   isUpdate = regOldData!=0;
1309   db = pParse->db;
1310   v = sqlite3GetVdbe(pParse);
1311   assert( v!=0 );
1312   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
1313   nCol = pTab->nCol;
1314 
1315   /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
1316   ** normal rowid tables.  nPkField is the number of key fields in the
1317   ** pPk index or 1 for a rowid table.  In other words, nPkField is the
1318   ** number of fields in the true primary key of the table. */
1319   if( HasRowid(pTab) ){
1320     pPk = 0;
1321     nPkField = 1;
1322   }else{
1323     pPk = sqlite3PrimaryKeyIndex(pTab);
1324     nPkField = pPk->nKeyCol;
1325   }
1326 
1327   /* Record that this module has started */
1328   VdbeModuleComment((v, "BEGIN: GenCnstCks(%d,%d,%d,%d,%d)",
1329                      iDataCur, iIdxCur, regNewData, regOldData, pkChng));
1330 
1331   /* Test all NOT NULL constraints.
1332   */
1333   for(i=0; i<nCol; i++){
1334     if( i==pTab->iPKey ){
1335       continue;        /* ROWID is never NULL */
1336     }
1337     if( aiChng && aiChng[i]<0 ){
1338       /* Don't bother checking for NOT NULL on columns that do not change */
1339       continue;
1340     }
1341     onError = pTab->aCol[i].notNull;
1342     if( onError==OE_None ) continue;  /* This column is allowed to be NULL */
1343     if( overrideError!=OE_Default ){
1344       onError = overrideError;
1345     }else if( onError==OE_Default ){
1346       onError = OE_Abort;
1347     }
1348     if( onError==OE_Replace && pTab->aCol[i].pDflt==0 ){
1349       onError = OE_Abort;
1350     }
1351     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
1352         || onError==OE_Ignore || onError==OE_Replace );
1353     switch( onError ){
1354       case OE_Abort:
1355         sqlite3MayAbort(pParse);
1356         /* Fall through */
1357       case OE_Rollback:
1358       case OE_Fail: {
1359         char *zMsg = sqlite3MPrintf(db, "%s.%s", pTab->zName,
1360                                     pTab->aCol[i].zName);
1361         sqlite3VdbeAddOp3(v, OP_HaltIfNull, SQLITE_CONSTRAINT_NOTNULL, onError,
1362                           regNewData+1+i);
1363         sqlite3VdbeAppendP4(v, zMsg, P4_DYNAMIC);
1364         sqlite3VdbeChangeP5(v, P5_ConstraintNotNull);
1365         VdbeCoverage(v);
1366         break;
1367       }
1368       case OE_Ignore: {
1369         sqlite3VdbeAddOp2(v, OP_IsNull, regNewData+1+i, ignoreDest);
1370         VdbeCoverage(v);
1371         break;
1372       }
1373       default: {
1374         assert( onError==OE_Replace );
1375         addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regNewData+1+i);
1376            VdbeCoverage(v);
1377         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regNewData+1+i);
1378         sqlite3VdbeJumpHere(v, addr1);
1379         break;
1380       }
1381     }
1382   }
1383 
1384   /* Test all CHECK constraints
1385   */
1386 #ifndef SQLITE_OMIT_CHECK
1387   if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
1388     ExprList *pCheck = pTab->pCheck;
1389     pParse->iSelfTab = -(regNewData+1);
1390     onError = overrideError!=OE_Default ? overrideError : OE_Abort;
1391     for(i=0; i<pCheck->nExpr; i++){
1392       int allOk;
1393       Expr *pExpr = pCheck->a[i].pExpr;
1394       if( aiChng
1395        && !sqlite3ExprReferencesUpdatedColumn(pExpr, aiChng, pkChng)
1396       ){
1397         /* The check constraints do not reference any of the columns being
1398         ** updated so there is no point it verifying the check constraint */
1399         continue;
1400       }
1401       allOk = sqlite3VdbeMakeLabel(v);
1402       sqlite3VdbeVerifyAbortable(v, onError);
1403       sqlite3ExprIfTrue(pParse, pExpr, allOk, SQLITE_JUMPIFNULL);
1404       if( onError==OE_Ignore ){
1405         sqlite3VdbeGoto(v, ignoreDest);
1406       }else{
1407         char *zName = pCheck->a[i].zName;
1408         if( zName==0 ) zName = pTab->zName;
1409         if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */
1410         sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_CHECK,
1411                               onError, zName, P4_TRANSIENT,
1412                               P5_ConstraintCheck);
1413       }
1414       sqlite3VdbeResolveLabel(v, allOk);
1415     }
1416     pParse->iSelfTab = 0;
1417   }
1418 #endif /* !defined(SQLITE_OMIT_CHECK) */
1419 
1420   /* UNIQUE and PRIMARY KEY constraints should be handled in the following
1421   ** order:
1422   **
1423   **   (1)  OE_Update
1424   **   (2)  OE_Abort, OE_Fail, OE_Rollback, OE_Ignore
1425   **   (3)  OE_Replace
1426   **
1427   ** OE_Fail and OE_Ignore must happen before any changes are made.
1428   ** OE_Update guarantees that only a single row will change, so it
1429   ** must happen before OE_Replace.  Technically, OE_Abort and OE_Rollback
1430   ** could happen in any order, but they are grouped up front for
1431   ** convenience.
1432   **
1433   ** 2018-08-14: Ticket https://www.sqlite.org/src/info/908f001483982c43
1434   ** The order of constraints used to have OE_Update as (2) and OE_Abort
1435   ** and so forth as (1). But apparently PostgreSQL checks the OE_Update
1436   ** constraint before any others, so it had to be moved.
1437   **
1438   ** Constraint checking code is generated in this order:
1439   **   (A)  The rowid constraint
1440   **   (B)  Unique index constraints that do not have OE_Replace as their
1441   **        default conflict resolution strategy
1442   **   (C)  Unique index that do use OE_Replace by default.
1443   **
1444   ** The ordering of (2) and (3) is accomplished by making sure the linked
1445   ** list of indexes attached to a table puts all OE_Replace indexes last
1446   ** in the list.  See sqlite3CreateIndex() for where that happens.
1447   */
1448 
1449   if( pUpsert ){
1450     if( pUpsert->pUpsertTarget==0 ){
1451       /* An ON CONFLICT DO NOTHING clause, without a constraint-target.
1452       ** Make all unique constraint resolution be OE_Ignore */
1453       assert( pUpsert->pUpsertSet==0 );
1454       overrideError = OE_Ignore;
1455       pUpsert = 0;
1456     }else if( (pUpIdx = pUpsert->pUpsertIdx)!=0 ){
1457       /* If the constraint-target uniqueness check must be run first.
1458       ** Jump to that uniqueness check now */
1459       upsertJump = sqlite3VdbeAddOp0(v, OP_Goto);
1460       VdbeComment((v, "UPSERT constraint goes first"));
1461     }
1462   }
1463 
1464   /* If rowid is changing, make sure the new rowid does not previously
1465   ** exist in the table.
1466   */
1467   if( pkChng && pPk==0 ){
1468     int addrRowidOk = sqlite3VdbeMakeLabel(v);
1469 
1470     /* Figure out what action to take in case of a rowid collision */
1471     onError = pTab->keyConf;
1472     if( overrideError!=OE_Default ){
1473       onError = overrideError;
1474     }else if( onError==OE_Default ){
1475       onError = OE_Abort;
1476     }
1477 
1478     /* figure out whether or not upsert applies in this case */
1479     if( pUpsert && pUpsert->pUpsertIdx==0 ){
1480       if( pUpsert->pUpsertSet==0 ){
1481         onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
1482       }else{
1483         onError = OE_Update;  /* DO UPDATE */
1484       }
1485     }
1486 
1487     /* If the response to a rowid conflict is REPLACE but the response
1488     ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
1489     ** to defer the running of the rowid conflict checking until after
1490     ** the UNIQUE constraints have run.
1491     */
1492     if( onError==OE_Replace      /* IPK rule is REPLACE */
1493      && onError!=overrideError   /* Rules for other contraints are different */
1494      && pTab->pIndex             /* There exist other constraints */
1495     ){
1496       ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
1497       VdbeComment((v, "defer IPK REPLACE until last"));
1498     }
1499 
1500     if( isUpdate ){
1501       /* pkChng!=0 does not mean that the rowid has changed, only that
1502       ** it might have changed.  Skip the conflict logic below if the rowid
1503       ** is unchanged. */
1504       sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
1505       sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
1506       VdbeCoverage(v);
1507     }
1508 
1509     /* Check to see if the new rowid already exists in the table.  Skip
1510     ** the following conflict logic if it does not. */
1511     VdbeNoopComment((v, "uniqueness check for ROWID"));
1512     sqlite3VdbeVerifyAbortable(v, onError);
1513     sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
1514     VdbeCoverage(v);
1515 
1516     switch( onError ){
1517       default: {
1518         onError = OE_Abort;
1519         /* Fall thru into the next case */
1520       }
1521       case OE_Rollback:
1522       case OE_Abort:
1523       case OE_Fail: {
1524         testcase( onError==OE_Rollback );
1525         testcase( onError==OE_Abort );
1526         testcase( onError==OE_Fail );
1527         sqlite3RowidConstraint(pParse, onError, pTab);
1528         break;
1529       }
1530       case OE_Replace: {
1531         /* If there are DELETE triggers on this table and the
1532         ** recursive-triggers flag is set, call GenerateRowDelete() to
1533         ** remove the conflicting row from the table. This will fire
1534         ** the triggers and remove both the table and index b-tree entries.
1535         **
1536         ** Otherwise, if there are no triggers or the recursive-triggers
1537         ** flag is not set, but the table has one or more indexes, call
1538         ** GenerateRowIndexDelete(). This removes the index b-tree entries
1539         ** only. The table b-tree entry will be replaced by the new entry
1540         ** when it is inserted.
1541         **
1542         ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
1543         ** also invoke MultiWrite() to indicate that this VDBE may require
1544         ** statement rollback (if the statement is aborted after the delete
1545         ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
1546         ** but being more selective here allows statements like:
1547         **
1548         **   REPLACE INTO t(rowid) VALUES($newrowid)
1549         **
1550         ** to run without a statement journal if there are no indexes on the
1551         ** table.
1552         */
1553         Trigger *pTrigger = 0;
1554         if( db->flags&SQLITE_RecTriggers ){
1555           pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
1556         }
1557         if( pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0) ){
1558           sqlite3MultiWrite(pParse);
1559           sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
1560                                    regNewData, 1, 0, OE_Replace, 1, -1);
1561         }else{
1562 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1563           assert( HasRowid(pTab) );
1564           /* This OP_Delete opcode fires the pre-update-hook only. It does
1565           ** not modify the b-tree. It is more efficient to let the coming
1566           ** OP_Insert replace the existing entry than it is to delete the
1567           ** existing entry and then insert a new one. */
1568           sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, OPFLAG_ISNOOP);
1569           sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
1570 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
1571           if( pTab->pIndex ){
1572             sqlite3MultiWrite(pParse);
1573             sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,-1);
1574           }
1575         }
1576         seenReplace = 1;
1577         break;
1578       }
1579 #ifndef SQLITE_OMIT_UPSERT
1580       case OE_Update: {
1581         sqlite3UpsertDoUpdate(pParse, pUpsert, pTab, 0, iDataCur);
1582         /* Fall through */
1583       }
1584 #endif
1585       case OE_Ignore: {
1586         testcase( onError==OE_Ignore );
1587         sqlite3VdbeGoto(v, ignoreDest);
1588         break;
1589       }
1590     }
1591     sqlite3VdbeResolveLabel(v, addrRowidOk);
1592     if( ipkTop ){
1593       ipkBottom = sqlite3VdbeAddOp0(v, OP_Goto);
1594       sqlite3VdbeJumpHere(v, ipkTop-1);
1595     }
1596   }
1597 
1598   /* Test all UNIQUE constraints by creating entries for each UNIQUE
1599   ** index and making sure that duplicate entries do not already exist.
1600   ** Compute the revised record entries for indices as we go.
1601   **
1602   ** This loop also handles the case of the PRIMARY KEY index for a
1603   ** WITHOUT ROWID table.
1604   */
1605   for(ix=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, ix++){
1606     int regIdx;          /* Range of registers hold conent for pIdx */
1607     int regR;            /* Range of registers holding conflicting PK */
1608     int iThisCur;        /* Cursor for this UNIQUE index */
1609     int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */
1610 
1611     if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */
1612     if( pUpIdx==pIdx ){
1613       addrUniqueOk = upsertJump+1;
1614       upsertBypass = sqlite3VdbeGoto(v, 0);
1615       VdbeComment((v, "Skip upsert subroutine"));
1616       sqlite3VdbeJumpHere(v, upsertJump);
1617     }else{
1618       addrUniqueOk = sqlite3VdbeMakeLabel(v);
1619     }
1620     if( bAffinityDone==0 && (pUpIdx==0 || pUpIdx==pIdx) ){
1621       sqlite3TableAffinity(v, pTab, regNewData+1);
1622       bAffinityDone = 1;
1623     }
1624     VdbeNoopComment((v, "uniqueness check for %s", pIdx->zName));
1625     iThisCur = iIdxCur+ix;
1626 
1627 
1628     /* Skip partial indices for which the WHERE clause is not true */
1629     if( pIdx->pPartIdxWhere ){
1630       sqlite3VdbeAddOp2(v, OP_Null, 0, aRegIdx[ix]);
1631       pParse->iSelfTab = -(regNewData+1);
1632       sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, addrUniqueOk,
1633                             SQLITE_JUMPIFNULL);
1634       pParse->iSelfTab = 0;
1635     }
1636 
1637     /* Create a record for this index entry as it should appear after
1638     ** the insert or update.  Store that record in the aRegIdx[ix] register
1639     */
1640     regIdx = aRegIdx[ix]+1;
1641     for(i=0; i<pIdx->nColumn; i++){
1642       int iField = pIdx->aiColumn[i];
1643       int x;
1644       if( iField==XN_EXPR ){
1645         pParse->iSelfTab = -(regNewData+1);
1646         sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[i].pExpr, regIdx+i);
1647         pParse->iSelfTab = 0;
1648         VdbeComment((v, "%s column %d", pIdx->zName, i));
1649       }else{
1650         if( iField==XN_ROWID || iField==pTab->iPKey ){
1651           x = regNewData;
1652         }else{
1653           x = iField + regNewData + 1;
1654         }
1655         sqlite3VdbeAddOp2(v, iField<0 ? OP_IntCopy : OP_SCopy, x, regIdx+i);
1656         VdbeComment((v, "%s", iField<0 ? "rowid" : pTab->aCol[iField].zName));
1657       }
1658     }
1659     sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn, aRegIdx[ix]);
1660     VdbeComment((v, "for %s", pIdx->zName));
1661 #ifdef SQLITE_ENABLE_NULL_TRIM
1662     if( pIdx->idxType==2 ) sqlite3SetMakeRecordP5(v, pIdx->pTable);
1663 #endif
1664 
1665     /* In an UPDATE operation, if this index is the PRIMARY KEY index
1666     ** of a WITHOUT ROWID table and there has been no change the
1667     ** primary key, then no collision is possible.  The collision detection
1668     ** logic below can all be skipped. */
1669     if( isUpdate && pPk==pIdx && pkChng==0 ){
1670       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1671       continue;
1672     }
1673 
1674     /* Find out what action to take in case there is a uniqueness conflict */
1675     onError = pIdx->onError;
1676     if( onError==OE_None ){
1677       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1678       continue;  /* pIdx is not a UNIQUE index */
1679     }
1680     if( overrideError!=OE_Default ){
1681       onError = overrideError;
1682     }else if( onError==OE_Default ){
1683       onError = OE_Abort;
1684     }
1685 
1686     /* Figure out if the upsert clause applies to this index */
1687     if( pUpIdx==pIdx ){
1688       if( pUpsert->pUpsertSet==0 ){
1689         onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
1690       }else{
1691         onError = OE_Update;  /* DO UPDATE */
1692       }
1693     }
1694 
1695     /* Collision detection may be omitted if all of the following are true:
1696     **   (1) The conflict resolution algorithm is REPLACE
1697     **   (2) The table is a WITHOUT ROWID table
1698     **   (3) There are no secondary indexes on the table
1699     **   (4) No delete triggers need to be fired if there is a conflict
1700     **   (5) No FK constraint counters need to be updated if a conflict occurs.
1701     */
1702     if( (ix==0 && pIdx->pNext==0)                   /* Condition 3 */
1703      && pPk==pIdx                                   /* Condition 2 */
1704      && onError==OE_Replace                         /* Condition 1 */
1705      && ( 0==(db->flags&SQLITE_RecTriggers) ||      /* Condition 4 */
1706           0==sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0))
1707      && ( 0==(db->flags&SQLITE_ForeignKeys) ||      /* Condition 5 */
1708          (0==pTab->pFKey && 0==sqlite3FkReferences(pTab)))
1709     ){
1710       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1711       continue;
1712     }
1713 
1714     /* Check to see if the new index entry will be unique */
1715     sqlite3VdbeVerifyAbortable(v, onError);
1716     sqlite3VdbeAddOp4Int(v, OP_NoConflict, iThisCur, addrUniqueOk,
1717                          regIdx, pIdx->nKeyCol); VdbeCoverage(v);
1718 
1719     /* Generate code to handle collisions */
1720     regR = (pIdx==pPk) ? regIdx : sqlite3GetTempRange(pParse, nPkField);
1721     if( isUpdate || onError==OE_Replace ){
1722       if( HasRowid(pTab) ){
1723         sqlite3VdbeAddOp2(v, OP_IdxRowid, iThisCur, regR);
1724         /* Conflict only if the rowid of the existing index entry
1725         ** is different from old-rowid */
1726         if( isUpdate ){
1727           sqlite3VdbeAddOp3(v, OP_Eq, regR, addrUniqueOk, regOldData);
1728           sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
1729           VdbeCoverage(v);
1730         }
1731       }else{
1732         int x;
1733         /* Extract the PRIMARY KEY from the end of the index entry and
1734         ** store it in registers regR..regR+nPk-1 */
1735         if( pIdx!=pPk ){
1736           for(i=0; i<pPk->nKeyCol; i++){
1737             assert( pPk->aiColumn[i]>=0 );
1738             x = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[i]);
1739             sqlite3VdbeAddOp3(v, OP_Column, iThisCur, x, regR+i);
1740             VdbeComment((v, "%s.%s", pTab->zName,
1741                          pTab->aCol[pPk->aiColumn[i]].zName));
1742           }
1743         }
1744         if( isUpdate ){
1745           /* If currently processing the PRIMARY KEY of a WITHOUT ROWID
1746           ** table, only conflict if the new PRIMARY KEY values are actually
1747           ** different from the old.
1748           **
1749           ** For a UNIQUE index, only conflict if the PRIMARY KEY values
1750           ** of the matched index row are different from the original PRIMARY
1751           ** KEY values of this row before the update.  */
1752           int addrJump = sqlite3VdbeCurrentAddr(v)+pPk->nKeyCol;
1753           int op = OP_Ne;
1754           int regCmp = (IsPrimaryKeyIndex(pIdx) ? regIdx : regR);
1755 
1756           for(i=0; i<pPk->nKeyCol; i++){
1757             char *p4 = (char*)sqlite3LocateCollSeq(pParse, pPk->azColl[i]);
1758             x = pPk->aiColumn[i];
1759             assert( x>=0 );
1760             if( i==(pPk->nKeyCol-1) ){
1761               addrJump = addrUniqueOk;
1762               op = OP_Eq;
1763             }
1764             sqlite3VdbeAddOp4(v, op,
1765                 regOldData+1+x, addrJump, regCmp+i, p4, P4_COLLSEQ
1766             );
1767             sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
1768             VdbeCoverageIf(v, op==OP_Eq);
1769             VdbeCoverageIf(v, op==OP_Ne);
1770           }
1771         }
1772       }
1773     }
1774 
1775     /* Generate code that executes if the new index entry is not unique */
1776     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
1777         || onError==OE_Ignore || onError==OE_Replace || onError==OE_Update );
1778     switch( onError ){
1779       case OE_Rollback:
1780       case OE_Abort:
1781       case OE_Fail: {
1782         testcase( onError==OE_Rollback );
1783         testcase( onError==OE_Abort );
1784         testcase( onError==OE_Fail );
1785         sqlite3UniqueConstraint(pParse, onError, pIdx);
1786         break;
1787       }
1788 #ifndef SQLITE_OMIT_UPSERT
1789       case OE_Update: {
1790         sqlite3UpsertDoUpdate(pParse, pUpsert, pTab, pIdx, iIdxCur+ix);
1791         /* Fall through */
1792       }
1793 #endif
1794       case OE_Ignore: {
1795         testcase( onError==OE_Ignore );
1796         sqlite3VdbeGoto(v, ignoreDest);
1797         break;
1798       }
1799       default: {
1800         Trigger *pTrigger = 0;
1801         assert( onError==OE_Replace );
1802         if( db->flags&SQLITE_RecTriggers ){
1803           pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
1804         }
1805         if( pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0) ){
1806           sqlite3MultiWrite(pParse);
1807         }
1808         sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
1809             regR, nPkField, 0, OE_Replace,
1810             (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
1811         seenReplace = 1;
1812         break;
1813       }
1814     }
1815     if( pUpIdx==pIdx ){
1816       sqlite3VdbeGoto(v, upsertJump+1);
1817       sqlite3VdbeJumpHere(v, upsertBypass);
1818     }else{
1819       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1820     }
1821     if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);
1822   }
1823 
1824   /* If the IPK constraint is a REPLACE, run it last */
1825   if( ipkTop ){
1826     sqlite3VdbeGoto(v, ipkTop+1);
1827     VdbeComment((v, "Do IPK REPLACE"));
1828     sqlite3VdbeJumpHere(v, ipkBottom);
1829   }
1830 
1831   *pbMayReplace = seenReplace;
1832   VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
1833 }
1834 
1835 #ifdef SQLITE_ENABLE_NULL_TRIM
1836 /*
1837 ** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
1838 ** to be the number of columns in table pTab that must not be NULL-trimmed.
1839 **
1840 ** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
1841 */
1842 void sqlite3SetMakeRecordP5(Vdbe *v, Table *pTab){
1843   u16 i;
1844 
1845   /* Records with omitted columns are only allowed for schema format
1846   ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
1847   if( pTab->pSchema->file_format<2 ) return;
1848 
1849   for(i=pTab->nCol-1; i>0; i--){
1850     if( pTab->aCol[i].pDflt!=0 ) break;
1851     if( pTab->aCol[i].colFlags & COLFLAG_PRIMKEY ) break;
1852   }
1853   sqlite3VdbeChangeP5(v, i+1);
1854 }
1855 #endif
1856 
1857 /*
1858 ** This routine generates code to finish the INSERT or UPDATE operation
1859 ** that was started by a prior call to sqlite3GenerateConstraintChecks.
1860 ** A consecutive range of registers starting at regNewData contains the
1861 ** rowid and the content to be inserted.
1862 **
1863 ** The arguments to this routine should be the same as the first six
1864 ** arguments to sqlite3GenerateConstraintChecks.
1865 */
1866 void sqlite3CompleteInsertion(
1867   Parse *pParse,      /* The parser context */
1868   Table *pTab,        /* the table into which we are inserting */
1869   int iDataCur,       /* Cursor of the canonical data source */
1870   int iIdxCur,        /* First index cursor */
1871   int regNewData,     /* Range of content */
1872   int *aRegIdx,       /* Register used by each index.  0 for unused indices */
1873   int update_flags,   /* True for UPDATE, False for INSERT */
1874   int appendBias,     /* True if this is likely to be an append */
1875   int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
1876 ){
1877   Vdbe *v;            /* Prepared statements under construction */
1878   Index *pIdx;        /* An index being inserted or updated */
1879   u8 pik_flags;       /* flag values passed to the btree insert */
1880   int regData;        /* Content registers (after the rowid) */
1881   int regRec;         /* Register holding assembled record for the table */
1882   int i;              /* Loop counter */
1883   u8 bAffinityDone = 0; /* True if OP_Affinity has been run already */
1884 
1885   assert( update_flags==0
1886        || update_flags==OPFLAG_ISUPDATE
1887        || update_flags==(OPFLAG_ISUPDATE|OPFLAG_SAVEPOSITION)
1888   );
1889 
1890   v = sqlite3GetVdbe(pParse);
1891   assert( v!=0 );
1892   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
1893   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
1894     if( aRegIdx[i]==0 ) continue;
1895     bAffinityDone = 1;
1896     if( pIdx->pPartIdxWhere ){
1897       sqlite3VdbeAddOp2(v, OP_IsNull, aRegIdx[i], sqlite3VdbeCurrentAddr(v)+2);
1898       VdbeCoverage(v);
1899     }
1900     pik_flags = (useSeekResult ? OPFLAG_USESEEKRESULT : 0);
1901     if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
1902       assert( pParse->nested==0 );
1903       pik_flags |= OPFLAG_NCHANGE;
1904       pik_flags |= (update_flags & OPFLAG_SAVEPOSITION);
1905 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1906       if( update_flags==0 ){
1907         sqlite3VdbeAddOp4(v, OP_InsertInt,
1908             iIdxCur+i, aRegIdx[i], 0, (char*)pTab, P4_TABLE
1909         );
1910         sqlite3VdbeChangeP5(v, OPFLAG_ISNOOP);
1911       }
1912 #endif
1913     }
1914     sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iIdxCur+i, aRegIdx[i],
1915                          aRegIdx[i]+1,
1916                          pIdx->uniqNotNull ? pIdx->nKeyCol: pIdx->nColumn);
1917     sqlite3VdbeChangeP5(v, pik_flags);
1918   }
1919   if( !HasRowid(pTab) ) return;
1920   regData = regNewData + 1;
1921   regRec = sqlite3GetTempReg(pParse);
1922   sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
1923   sqlite3SetMakeRecordP5(v, pTab);
1924   if( !bAffinityDone ){
1925     sqlite3TableAffinity(v, pTab, 0);
1926   }
1927   if( pParse->nested ){
1928     pik_flags = 0;
1929   }else{
1930     pik_flags = OPFLAG_NCHANGE;
1931     pik_flags |= (update_flags?update_flags:OPFLAG_LASTROWID);
1932   }
1933   if( appendBias ){
1934     pik_flags |= OPFLAG_APPEND;
1935   }
1936   if( useSeekResult ){
1937     pik_flags |= OPFLAG_USESEEKRESULT;
1938   }
1939   sqlite3VdbeAddOp3(v, OP_Insert, iDataCur, regRec, regNewData);
1940   if( !pParse->nested ){
1941     sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
1942   }
1943   sqlite3VdbeChangeP5(v, pik_flags);
1944 }
1945 
1946 /*
1947 ** Allocate cursors for the pTab table and all its indices and generate
1948 ** code to open and initialized those cursors.
1949 **
1950 ** The cursor for the object that contains the complete data (normally
1951 ** the table itself, but the PRIMARY KEY index in the case of a WITHOUT
1952 ** ROWID table) is returned in *piDataCur.  The first index cursor is
1953 ** returned in *piIdxCur.  The number of indices is returned.
1954 **
1955 ** Use iBase as the first cursor (either the *piDataCur for rowid tables
1956 ** or the first index for WITHOUT ROWID tables) if it is non-negative.
1957 ** If iBase is negative, then allocate the next available cursor.
1958 **
1959 ** For a rowid table, *piDataCur will be exactly one less than *piIdxCur.
1960 ** For a WITHOUT ROWID table, *piDataCur will be somewhere in the range
1961 ** of *piIdxCurs, depending on where the PRIMARY KEY index appears on the
1962 ** pTab->pIndex list.
1963 **
1964 ** If pTab is a virtual table, then this routine is a no-op and the
1965 ** *piDataCur and *piIdxCur values are left uninitialized.
1966 */
1967 int sqlite3OpenTableAndIndices(
1968   Parse *pParse,   /* Parsing context */
1969   Table *pTab,     /* Table to be opened */
1970   int op,          /* OP_OpenRead or OP_OpenWrite */
1971   u8 p5,           /* P5 value for OP_Open* opcodes (except on WITHOUT ROWID) */
1972   int iBase,       /* Use this for the table cursor, if there is one */
1973   u8 *aToOpen,     /* If not NULL: boolean for each table and index */
1974   int *piDataCur,  /* Write the database source cursor number here */
1975   int *piIdxCur    /* Write the first index cursor number here */
1976 ){
1977   int i;
1978   int iDb;
1979   int iDataCur;
1980   Index *pIdx;
1981   Vdbe *v;
1982 
1983   assert( op==OP_OpenRead || op==OP_OpenWrite );
1984   assert( op==OP_OpenWrite || p5==0 );
1985   if( IsVirtual(pTab) ){
1986     /* This routine is a no-op for virtual tables. Leave the output
1987     ** variables *piDataCur and *piIdxCur uninitialized so that valgrind
1988     ** can detect if they are used by mistake in the caller. */
1989     return 0;
1990   }
1991   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
1992   v = sqlite3GetVdbe(pParse);
1993   assert( v!=0 );
1994   if( iBase<0 ) iBase = pParse->nTab;
1995   iDataCur = iBase++;
1996   if( piDataCur ) *piDataCur = iDataCur;
1997   if( HasRowid(pTab) && (aToOpen==0 || aToOpen[0]) ){
1998     sqlite3OpenTable(pParse, iDataCur, iDb, pTab, op);
1999   }else{
2000     sqlite3TableLock(pParse, iDb, pTab->tnum, op==OP_OpenWrite, pTab->zName);
2001   }
2002   if( piIdxCur ) *piIdxCur = iBase;
2003   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
2004     int iIdxCur = iBase++;
2005     assert( pIdx->pSchema==pTab->pSchema );
2006     if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
2007       if( piDataCur ) *piDataCur = iIdxCur;
2008       p5 = 0;
2009     }
2010     if( aToOpen==0 || aToOpen[i+1] ){
2011       sqlite3VdbeAddOp3(v, op, iIdxCur, pIdx->tnum, iDb);
2012       sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
2013       sqlite3VdbeChangeP5(v, p5);
2014       VdbeComment((v, "%s", pIdx->zName));
2015     }
2016   }
2017   if( iBase>pParse->nTab ) pParse->nTab = iBase;
2018   return i;
2019 }
2020 
2021 
2022 #ifdef SQLITE_TEST
2023 /*
2024 ** The following global variable is incremented whenever the
2025 ** transfer optimization is used.  This is used for testing
2026 ** purposes only - to make sure the transfer optimization really
2027 ** is happening when it is supposed to.
2028 */
2029 int sqlite3_xferopt_count;
2030 #endif /* SQLITE_TEST */
2031 
2032 
2033 #ifndef SQLITE_OMIT_XFER_OPT
2034 /*
2035 ** Check to see if index pSrc is compatible as a source of data
2036 ** for index pDest in an insert transfer optimization.  The rules
2037 ** for a compatible index:
2038 **
2039 **    *   The index is over the same set of columns
2040 **    *   The same DESC and ASC markings occurs on all columns
2041 **    *   The same onError processing (OE_Abort, OE_Ignore, etc)
2042 **    *   The same collating sequence on each column
2043 **    *   The index has the exact same WHERE clause
2044 */
2045 static int xferCompatibleIndex(Index *pDest, Index *pSrc){
2046   int i;
2047   assert( pDest && pSrc );
2048   assert( pDest->pTable!=pSrc->pTable );
2049   if( pDest->nKeyCol!=pSrc->nKeyCol ){
2050     return 0;   /* Different number of columns */
2051   }
2052   if( pDest->onError!=pSrc->onError ){
2053     return 0;   /* Different conflict resolution strategies */
2054   }
2055   for(i=0; i<pSrc->nKeyCol; i++){
2056     if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
2057       return 0;   /* Different columns indexed */
2058     }
2059     if( pSrc->aiColumn[i]==XN_EXPR ){
2060       assert( pSrc->aColExpr!=0 && pDest->aColExpr!=0 );
2061       if( sqlite3ExprCompare(0, pSrc->aColExpr->a[i].pExpr,
2062                              pDest->aColExpr->a[i].pExpr, -1)!=0 ){
2063         return 0;   /* Different expressions in the index */
2064       }
2065     }
2066     if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
2067       return 0;   /* Different sort orders */
2068     }
2069     if( sqlite3_stricmp(pSrc->azColl[i],pDest->azColl[i])!=0 ){
2070       return 0;   /* Different collating sequences */
2071     }
2072   }
2073   if( sqlite3ExprCompare(0, pSrc->pPartIdxWhere, pDest->pPartIdxWhere, -1) ){
2074     return 0;     /* Different WHERE clauses */
2075   }
2076 
2077   /* If no test above fails then the indices must be compatible */
2078   return 1;
2079 }
2080 
2081 /*
2082 ** Attempt the transfer optimization on INSERTs of the form
2083 **
2084 **     INSERT INTO tab1 SELECT * FROM tab2;
2085 **
2086 ** The xfer optimization transfers raw records from tab2 over to tab1.
2087 ** Columns are not decoded and reassembled, which greatly improves
2088 ** performance.  Raw index records are transferred in the same way.
2089 **
2090 ** The xfer optimization is only attempted if tab1 and tab2 are compatible.
2091 ** There are lots of rules for determining compatibility - see comments
2092 ** embedded in the code for details.
2093 **
2094 ** This routine returns TRUE if the optimization is guaranteed to be used.
2095 ** Sometimes the xfer optimization will only work if the destination table
2096 ** is empty - a factor that can only be determined at run-time.  In that
2097 ** case, this routine generates code for the xfer optimization but also
2098 ** does a test to see if the destination table is empty and jumps over the
2099 ** xfer optimization code if the test fails.  In that case, this routine
2100 ** returns FALSE so that the caller will know to go ahead and generate
2101 ** an unoptimized transfer.  This routine also returns FALSE if there
2102 ** is no chance that the xfer optimization can be applied.
2103 **
2104 ** This optimization is particularly useful at making VACUUM run faster.
2105 */
2106 static int xferOptimization(
2107   Parse *pParse,        /* Parser context */
2108   Table *pDest,         /* The table we are inserting into */
2109   Select *pSelect,      /* A SELECT statement to use as the data source */
2110   int onError,          /* How to handle constraint errors */
2111   int iDbDest           /* The database of pDest */
2112 ){
2113   sqlite3 *db = pParse->db;
2114   ExprList *pEList;                /* The result set of the SELECT */
2115   Table *pSrc;                     /* The table in the FROM clause of SELECT */
2116   Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
2117   struct SrcList_item *pItem;      /* An element of pSelect->pSrc */
2118   int i;                           /* Loop counter */
2119   int iDbSrc;                      /* The database of pSrc */
2120   int iSrc, iDest;                 /* Cursors from source and destination */
2121   int addr1, addr2;                /* Loop addresses */
2122   int emptyDestTest = 0;           /* Address of test for empty pDest */
2123   int emptySrcTest = 0;            /* Address of test for empty pSrc */
2124   Vdbe *v;                         /* The VDBE we are building */
2125   int regAutoinc;                  /* Memory register used by AUTOINC */
2126   int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */
2127   int regData, regRowid;           /* Registers holding data and rowid */
2128 
2129   if( pSelect==0 ){
2130     return 0;   /* Must be of the form  INSERT INTO ... SELECT ... */
2131   }
2132   if( pParse->pWith || pSelect->pWith ){
2133     /* Do not attempt to process this query if there are an WITH clauses
2134     ** attached to it. Proceeding may generate a false "no such table: xxx"
2135     ** error if pSelect reads from a CTE named "xxx".  */
2136     return 0;
2137   }
2138   if( sqlite3TriggerList(pParse, pDest) ){
2139     return 0;   /* tab1 must not have triggers */
2140   }
2141 #ifndef SQLITE_OMIT_VIRTUALTABLE
2142   if( IsVirtual(pDest) ){
2143     return 0;   /* tab1 must not be a virtual table */
2144   }
2145 #endif
2146   if( onError==OE_Default ){
2147     if( pDest->iPKey>=0 ) onError = pDest->keyConf;
2148     if( onError==OE_Default ) onError = OE_Abort;
2149   }
2150   assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
2151   if( pSelect->pSrc->nSrc!=1 ){
2152     return 0;   /* FROM clause must have exactly one term */
2153   }
2154   if( pSelect->pSrc->a[0].pSelect ){
2155     return 0;   /* FROM clause cannot contain a subquery */
2156   }
2157   if( pSelect->pWhere ){
2158     return 0;   /* SELECT may not have a WHERE clause */
2159   }
2160   if( pSelect->pOrderBy ){
2161     return 0;   /* SELECT may not have an ORDER BY clause */
2162   }
2163   /* Do not need to test for a HAVING clause.  If HAVING is present but
2164   ** there is no ORDER BY, we will get an error. */
2165   if( pSelect->pGroupBy ){
2166     return 0;   /* SELECT may not have a GROUP BY clause */
2167   }
2168   if( pSelect->pLimit ){
2169     return 0;   /* SELECT may not have a LIMIT clause */
2170   }
2171   if( pSelect->pPrior ){
2172     return 0;   /* SELECT may not be a compound query */
2173   }
2174   if( pSelect->selFlags & SF_Distinct ){
2175     return 0;   /* SELECT may not be DISTINCT */
2176   }
2177   pEList = pSelect->pEList;
2178   assert( pEList!=0 );
2179   if( pEList->nExpr!=1 ){
2180     return 0;   /* The result set must have exactly one column */
2181   }
2182   assert( pEList->a[0].pExpr );
2183   if( pEList->a[0].pExpr->op!=TK_ASTERISK ){
2184     return 0;   /* The result set must be the special operator "*" */
2185   }
2186 
2187   /* At this point we have established that the statement is of the
2188   ** correct syntactic form to participate in this optimization.  Now
2189   ** we have to check the semantics.
2190   */
2191   pItem = pSelect->pSrc->a;
2192   pSrc = sqlite3LocateTableItem(pParse, 0, pItem);
2193   if( pSrc==0 ){
2194     return 0;   /* FROM clause does not contain a real table */
2195   }
2196   if( pSrc==pDest ){
2197     return 0;   /* tab1 and tab2 may not be the same table */
2198   }
2199   if( HasRowid(pDest)!=HasRowid(pSrc) ){
2200     return 0;   /* source and destination must both be WITHOUT ROWID or not */
2201   }
2202 #ifndef SQLITE_OMIT_VIRTUALTABLE
2203   if( IsVirtual(pSrc) ){
2204     return 0;   /* tab2 must not be a virtual table */
2205   }
2206 #endif
2207   if( pSrc->pSelect ){
2208     return 0;   /* tab2 may not be a view */
2209   }
2210   if( pDest->nCol!=pSrc->nCol ){
2211     return 0;   /* Number of columns must be the same in tab1 and tab2 */
2212   }
2213   if( pDest->iPKey!=pSrc->iPKey ){
2214     return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
2215   }
2216   for(i=0; i<pDest->nCol; i++){
2217     Column *pDestCol = &pDest->aCol[i];
2218     Column *pSrcCol = &pSrc->aCol[i];
2219 #ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
2220     if( (db->mDbFlags & DBFLAG_Vacuum)==0
2221      && (pDestCol->colFlags | pSrcCol->colFlags) & COLFLAG_HIDDEN
2222     ){
2223       return 0;    /* Neither table may have __hidden__ columns */
2224     }
2225 #endif
2226     if( pDestCol->affinity!=pSrcCol->affinity ){
2227       return 0;    /* Affinity must be the same on all columns */
2228     }
2229     if( sqlite3_stricmp(pDestCol->zColl, pSrcCol->zColl)!=0 ){
2230       return 0;    /* Collating sequence must be the same on all columns */
2231     }
2232     if( pDestCol->notNull && !pSrcCol->notNull ){
2233       return 0;    /* tab2 must be NOT NULL if tab1 is */
2234     }
2235     /* Default values for second and subsequent columns need to match. */
2236     if( i>0 ){
2237       assert( pDestCol->pDflt==0 || pDestCol->pDflt->op==TK_SPAN );
2238       assert( pSrcCol->pDflt==0 || pSrcCol->pDflt->op==TK_SPAN );
2239       if( (pDestCol->pDflt==0)!=(pSrcCol->pDflt==0)
2240        || (pDestCol->pDflt && strcmp(pDestCol->pDflt->u.zToken,
2241                                        pSrcCol->pDflt->u.zToken)!=0)
2242       ){
2243         return 0;    /* Default values must be the same for all columns */
2244       }
2245     }
2246   }
2247   for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
2248     if( IsUniqueIndex(pDestIdx) ){
2249       destHasUniqueIdx = 1;
2250     }
2251     for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
2252       if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
2253     }
2254     if( pSrcIdx==0 ){
2255       return 0;    /* pDestIdx has no corresponding index in pSrc */
2256     }
2257   }
2258 #ifndef SQLITE_OMIT_CHECK
2259   if( pDest->pCheck && sqlite3ExprListCompare(pSrc->pCheck,pDest->pCheck,-1) ){
2260     return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
2261   }
2262 #endif
2263 #ifndef SQLITE_OMIT_FOREIGN_KEY
2264   /* Disallow the transfer optimization if the destination table constains
2265   ** any foreign key constraints.  This is more restrictive than necessary.
2266   ** But the main beneficiary of the transfer optimization is the VACUUM
2267   ** command, and the VACUUM command disables foreign key constraints.  So
2268   ** the extra complication to make this rule less restrictive is probably
2269   ** not worth the effort.  Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
2270   */
2271   if( (db->flags & SQLITE_ForeignKeys)!=0 && pDest->pFKey!=0 ){
2272     return 0;
2273   }
2274 #endif
2275   if( (db->flags & SQLITE_CountRows)!=0 ){
2276     return 0;  /* xfer opt does not play well with PRAGMA count_changes */
2277   }
2278 
2279   /* If we get this far, it means that the xfer optimization is at
2280   ** least a possibility, though it might only work if the destination
2281   ** table (tab1) is initially empty.
2282   */
2283 #ifdef SQLITE_TEST
2284   sqlite3_xferopt_count++;
2285 #endif
2286   iDbSrc = sqlite3SchemaToIndex(db, pSrc->pSchema);
2287   v = sqlite3GetVdbe(pParse);
2288   sqlite3CodeVerifySchema(pParse, iDbSrc);
2289   iSrc = pParse->nTab++;
2290   iDest = pParse->nTab++;
2291   regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
2292   regData = sqlite3GetTempReg(pParse);
2293   regRowid = sqlite3GetTempReg(pParse);
2294   sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
2295   assert( HasRowid(pDest) || destHasUniqueIdx );
2296   if( (db->mDbFlags & DBFLAG_Vacuum)==0 && (
2297       (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
2298    || destHasUniqueIdx                              /* (2) */
2299    || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
2300   )){
2301     /* In some circumstances, we are able to run the xfer optimization
2302     ** only if the destination table is initially empty. Unless the
2303     ** DBFLAG_Vacuum flag is set, this block generates code to make
2304     ** that determination. If DBFLAG_Vacuum is set, then the destination
2305     ** table is always empty.
2306     **
2307     ** Conditions under which the destination must be empty:
2308     **
2309     ** (1) There is no INTEGER PRIMARY KEY but there are indices.
2310     **     (If the destination is not initially empty, the rowid fields
2311     **     of index entries might need to change.)
2312     **
2313     ** (2) The destination has a unique index.  (The xfer optimization
2314     **     is unable to test uniqueness.)
2315     **
2316     ** (3) onError is something other than OE_Abort and OE_Rollback.
2317     */
2318     addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0); VdbeCoverage(v);
2319     emptyDestTest = sqlite3VdbeAddOp0(v, OP_Goto);
2320     sqlite3VdbeJumpHere(v, addr1);
2321   }
2322   if( HasRowid(pSrc) ){
2323     u8 insFlags;
2324     sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
2325     emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
2326     if( pDest->iPKey>=0 ){
2327       addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
2328       sqlite3VdbeVerifyAbortable(v, onError);
2329       addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
2330       VdbeCoverage(v);
2331       sqlite3RowidConstraint(pParse, onError, pDest);
2332       sqlite3VdbeJumpHere(v, addr2);
2333       autoIncStep(pParse, regAutoinc, regRowid);
2334     }else if( pDest->pIndex==0 ){
2335       addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
2336     }else{
2337       addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
2338       assert( (pDest->tabFlags & TF_Autoincrement)==0 );
2339     }
2340     sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
2341     if( db->mDbFlags & DBFLAG_Vacuum ){
2342       sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
2343       insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|
2344                            OPFLAG_APPEND|OPFLAG_USESEEKRESULT;
2345     }else{
2346       insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND;
2347     }
2348     sqlite3VdbeAddOp4(v, OP_Insert, iDest, regData, regRowid,
2349                       (char*)pDest, P4_TABLE);
2350     sqlite3VdbeChangeP5(v, insFlags);
2351     sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1); VdbeCoverage(v);
2352     sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
2353     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
2354   }else{
2355     sqlite3TableLock(pParse, iDbDest, pDest->tnum, 1, pDest->zName);
2356     sqlite3TableLock(pParse, iDbSrc, pSrc->tnum, 0, pSrc->zName);
2357   }
2358   for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
2359     u8 idxInsFlags = 0;
2360     for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
2361       if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
2362     }
2363     assert( pSrcIdx );
2364     sqlite3VdbeAddOp3(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc);
2365     sqlite3VdbeSetP4KeyInfo(pParse, pSrcIdx);
2366     VdbeComment((v, "%s", pSrcIdx->zName));
2367     sqlite3VdbeAddOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest);
2368     sqlite3VdbeSetP4KeyInfo(pParse, pDestIdx);
2369     sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR);
2370     VdbeComment((v, "%s", pDestIdx->zName));
2371     addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
2372     sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
2373     if( db->mDbFlags & DBFLAG_Vacuum ){
2374       /* This INSERT command is part of a VACUUM operation, which guarantees
2375       ** that the destination table is empty. If all indexed columns use
2376       ** collation sequence BINARY, then it can also be assumed that the
2377       ** index will be populated by inserting keys in strictly sorted
2378       ** order. In this case, instead of seeking within the b-tree as part
2379       ** of every OP_IdxInsert opcode, an OP_SeekEnd is added before the
2380       ** OP_IdxInsert to seek to the point within the b-tree where each key
2381       ** should be inserted. This is faster.
2382       **
2383       ** If any of the indexed columns use a collation sequence other than
2384       ** BINARY, this optimization is disabled. This is because the user
2385       ** might change the definition of a collation sequence and then run
2386       ** a VACUUM command. In that case keys may not be written in strictly
2387       ** sorted order.  */
2388       for(i=0; i<pSrcIdx->nColumn; i++){
2389         const char *zColl = pSrcIdx->azColl[i];
2390         if( sqlite3_stricmp(sqlite3StrBINARY, zColl) ) break;
2391       }
2392       if( i==pSrcIdx->nColumn ){
2393         idxInsFlags = OPFLAG_USESEEKRESULT;
2394         sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
2395       }
2396     }
2397     if( !HasRowid(pSrc) && pDestIdx->idxType==2 ){
2398       idxInsFlags |= OPFLAG_NCHANGE;
2399     }
2400     sqlite3VdbeAddOp2(v, OP_IdxInsert, iDest, regData);
2401     sqlite3VdbeChangeP5(v, idxInsFlags|OPFLAG_APPEND);
2402     sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1); VdbeCoverage(v);
2403     sqlite3VdbeJumpHere(v, addr1);
2404     sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
2405     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
2406   }
2407   if( emptySrcTest ) sqlite3VdbeJumpHere(v, emptySrcTest);
2408   sqlite3ReleaseTempReg(pParse, regRowid);
2409   sqlite3ReleaseTempReg(pParse, regData);
2410   if( emptyDestTest ){
2411     sqlite3AutoincrementEnd(pParse);
2412     sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
2413     sqlite3VdbeJumpHere(v, emptyDestTest);
2414     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
2415     return 0;
2416   }else{
2417     return 1;
2418   }
2419 }
2420 #endif /* SQLITE_OMIT_XFER_OPT */
2421